1 BACKGROUND

We are assessing the utility and feasibility of instrumenting Ziphius cavirostris off Cape Hatteras with fastloc capabale wildlife computer splash tags for the atlbrs.

We have deployed a total of 5 fastloc capable tags between 2018 and 2023. The first tag deployed in 2018 was programmed to only collect fastloc data and no dive data. The follow 4 tags were programmed to collect both time-series dive data and fastloc positions. Settings details can be found below.

Each fastloc data message consists of the data required to calculate a single fastloc position. As a comparison at 5-minute sampling period a single time-series data message spans 4 hours of recording. Therefore if we attempt to generate even hourly fastloc positions, our data queue for fastloc quickly surpasses the bandwidth requirements for dive data alone. Therefore it is unlikely even if we forego all other data streams that we would be able to densely sample the movement of an instrumented animals during the time scale of a single treatment event which last from 30 minutes to 1 hour and with a window of highest interest extending 24 hours past the conclusion of the treatment.

Therefore, there are two main questions regarding the use of fastloc tags in the atlbrs:

  1. Can the programming be tuned to produce a satisfactorily continuous dive data record along side some fastloc positions.
  2. Is the number of fastloc positions produced (and received) by this tuning sufficient to increase precision and accuracy of modeled positional tracks above what argos alone already provides at a relevant time scale to our treatments.

2 METHODS

2.1 programming

We used two tag programming configurations: (1) a fastloc only configuration, and (2) a time-series and fastloc configuration. Programming highlights:

fastloc only configuration fastloc and time-series configuration
fastloc:
- 2/hr max successful fastloc attempts
- 4/hr max failed fastloc attempts
- 96/day overall max fastloc attempts
- 0-23 fastloc attempt hours
- unlimited collection period		 fastloc:
- 1/hr max successful fastloc attempts
- 4/hr max failed fastloc attempts
- 40/day overall max fastloc attempts
- 3-4, 9-10, 15-16, 21-22 fastloc attempt hours
- 21 day collection period
argos tx:
- 470 daily tx
- 24 hours initial tx, then:
- 0-3, 7-23 tx hours		 argos tx:
- 470 daily tx
- 24 hours initial tx, then:
- 0-3, 8-11, 12-23 tx hours
time-series:
- depth
- 5-minute sampling peirod
- 14 day collection period
buffer and tx priority:
- 2 day data buffer
- high priority fastloc		 buffer and tx priority:
- 100 day data buffer
- high priority time-series and fastloc

2.2 summary

2.3 accuracy and precision assessment

3 RESULTS

3.1 instrumentation details

ZcTag077_DUML

  • catalog id:Zca_015_HAT
  • previously tagged ZcTag039
  • adult male
  • first seen 2015
  • fastloc only programming

ZcTag143_DUML

  • catalog id: Zca_098_HAT
  • previously tagged: ZcTag102_DUML
  • adult male
  • first seen 2020
  • perhaps eroded or missing teeth
  • fastloc and time-series programming

ZcTag144_DUML

  • catalog id: ???
  • adult male
  • fastloc and time-series programming

ZcTag145_DUML

  • catalog id: ???
  • unknown age unknown sex
  • fastloc and time-series programming

ZcTag146_DUML

  • catalog id: Zca_072_HAT
  • unknown age male (genetically determined)
  • first seen 2019
  • fastloc and time-series programming

3.2 locations

ZcTag077_DUML

quality 0 1 2 3 A B gps ndays
count 55 9 3 1 28 92 179 23.7
per day 2.3 0.4 0.1 0 1.2 3.9 7.6

ZcTag143_DUML

quality 0 1 2 3 A B gps Z ndays ndays gps
count 231 68 19 1 118 323 81 2 67.3 21
per day 3.4 1 0.3 0 1.8 4.8 3.9 0

ZcTag144_DUML

quality 0 1 2 3 A B gps ndays ndays gps
count 83 21 6 1 71 217 47 37.9 21
per day 2.2 0.6 0.2 0 1.9 5.7 2.2

ZcTag145_DUML

quality 0 1 2 A B gps ndays ndays gps
count 20 2 2 8 35 3 5.2 5.2
per day 3.8 0.4 0.4 1.5 6.7 0.6 1

ZcTag146_DUML

quality 0 1 2 3 A B gps ndays ndays gps
count 363 113 33 10 117 307 65 68.8 21
per day 5.3 1.6 0.5 0.1 1.7 4.5 3.1

3.3 failed versus successful fastlocs

3.4 dive data and health status

PROVISIONAL plot status cutoffs and bat voltage. Cutoffs are in dotted red lines. These are either:

  1. healthy tags: the last status messages as a conservative cutoff and on tags that are still actively transmitting this is likely to increase
  2. unhealthy pressure transducer tags: if there are 2 status messages (crc’d) where the | zerodepth | > 10 then this is the last good status message before the 1st of those two bad messages.

We have settled on a more complicated cutoff system to capture a little more very likely good data. For detail please see DATAPREP_sattag_processing. But this gives you a general idea of approx. cutoffs and pressure transducer health.

3.5 impact on accuracy and precision

deployid mean0 mean_gps sd0 sd_gps
ZcTag077_DUML 7.98 2.68 5.29 2.75
ZcTag143_DUML 10.69 6.39 10.99 6.96
ZcTag144_DUML 7.07 5.37 4.18 3.34
ZcTag146_DUML 7.68 5.64 4.34 4.43